Water heater



y 1933. w. G. MILLER 1,908,041

WATER HEATER Filed Sept. 18, 1931 Patented May 9, 1933 UNITED STATES PATENT OFFICE WALTER G. MILLER, OF CHICAGO, ILLINOIS WATER HEATER Application filed September 18, 1931. Serial N0. 563,563.

In the ordinary types of water heaters to be only a comparatively small quantity of supply hot water for household, use, the this soft water, confined in a closed system, water to be consumed comes in direct contact after any mineral matter originally conwith the metal surfaces that are heated by tained in the water has once been precipithe gas or other flame. Consequently the tated, there will be no further precipitation Water is raised to a temperature high enough that would form an objectionable coating or to cause precipitation of the lime in hard scale in the coils. In other words, even water and, Where hard water is being used, though the heating medium initially conthe heating coils soon become so caked as sisted ofv hard water, there would be very to burn out readily. It sometimes happens little mineral matter that could be precipithat a heating coil will burn out in a few tated, this inconsiderable amount of minweeks. eral matter being probably unobjectionable.

The object of the present invention is to The various features of novelty whereby produce a heater for heating either hard or my invention is characterized will hereinsoft water, without danger of precipitation after he pointed out with particularity in the and thereby cutting down the efficiency of claims; but, for a full understanding of my the apparatus and shortening its life. invention and of its objects and advantages,

Allv that is necessary in order to overcome reference may be had to the following dethe difiiculty to which I have just referred, tailed description taken in connection with is to insure that hard water will at no time the accompanying drawing, wherein: be raised to the temperature at which the Figure 1 is a view partly in elevation and minerals will separate therefrom; this being partly in vertical section through a heater usually the boiling point of the water. embodying the present invention; Fig. 2 is However, if the water to be consumed cona view partly in elevation and partly in sectacts with one side of a metal part whose tion, on a somewhat larger scale than Fig. 1, opposite side is exposed to a flame. it is imshowing a fragment of the system; and Fig. possible in actual practice to avoid the sep- 3 is an end view of the radiator or heataration of the mineral matter in hard water. interchanger.

Therefore, in accordance with my invention, In the drawing I have illustrated my in- 30 I indirectly heat the water to be consumed, vention as applied to a conventional type 30 by means of a heat interchanger through of hot water heater in which there is a tank, which flows a heating medium whose tema burner and a coil through which water perature may be controlled. By properly seflows and to which heat is transmitted from lecting the heatinT medium that flows the burner and, for the sake of brevity, the

35 through the heat inter-changer, it will make detailed description will be confined to this no difference whether this heating medium particular embodiment, although the invenbe raised to or above the temperature of the tion is not limited thereto. boiling point of water at the time it is re- Referring to the drawing, 1 represents a ceiving heat from the flame or other source; tall tank provided with an inlet pipe 2 for 0 and, therefore, as long as the temperature of cold water, and an outlet or a service pipe this heating medium is controlled so that 3 for hot water. Normally the tank will be the heater interchangcr does not become too filled with water, indicated at A. hot, the objections to which I have referred In accordance with my invention I mount will be avoided, regardless of the temperawithin the tank a heat interchanger 4 of ture to which the heating medium may be considerable capacity. In the ordinary raised at the point of transmission of heat small tank for household use,a radiator havthereto. Ordinarily the heating medium ing nine or ten square feet of radiating surmay consist simply of soft water, convenientface will usually be found to be sufficient. ly rain water, containing no minerals to be The water in the tank is heated bythe heat 0 precipitated. Furthermore, since there will interchanger which, in turn, receives heat from a heating medium flowing through the same. In the arrangement shown, the radiator is in a closed circuit which also contains a second heat interchanger in the form of a heating coil 5 exterior to the tank. The bottom of the radiator is connected to the lower end of the coil by a pipe 6, whereas there is a pipe line 7 between the upper ends of the radiator and the coil. The coil is shown as arranged in the usual or any suitable casing or shell 8 in the bottom of which is a gas burner 9. The heating coil is preferably disposed at a lower level than the radiator, to facilitate circulation of the liquid through the closed system when the burner is lighted.

Gas is supplied to the burner through a pipe 10. By placing in this pipe a thermostatic valve 11 whose thermal element 12 extends into the tank, the gas may be shut ofi automatically whenever the water in the tank or in that region of the tank in which the thermal element is located, reaches a desired maximum temperature.

As heretofore stated, it makes very little difference what the temperature is to which the water or other medium is temporarily heated in the coil 5, as long as the radiator does not become hot enough to cause separation or precipitation of the minerals contained in the water in the tank. Possibly the water or other heating medium, if the temperature were uncontrolled, might be heated to a degree that would cause the radiator to become too hot. I have, therefore, an additional controlling means for the burner, whereby the gas will be turned off in the event that the temperature of the water or other heating fluid entering the top of the radiator exceeds a certain maximumt' To this end I have provided the pipe line 7t} with a small standpipe 14 near the point where this pipe line connects with the top of the radiator. Extending down into the standpipe is the thermal element 15 of a second thermostatic valve 16 disposed in the gas supply pipe 10. This standpipe, which also serves as an expansion chamber, is partially filled with the water or other heating liquid whose temperature is at least as high as that of the liquid flowing into the radiator. If the temperature in the standpipe should become too high, the flow of gas will be reduced or cut oil entirely, depending upon whether or not a pilot light is employed.

The top of the standpipe is closed by a cap 17 to which there are two connections. One of these connections, 18, is from a funnel 19 through which the system may be filled with water or other liquid; the connection being closed by a valve 20 after the system has been filled. The other connection, 21, terminates in a suitable safety valve 22. In the event that steam should be formed in the closed system, and the pressure become too great, the pressure will be relieved by the safety valve.

Frequently householders shut off the gas from these heaters in winter and heat the water from a coil placed in the fire box of the boiler or furnace. The heat interchanger in my design, could be connected to such a coil, although it would be very difficult to control the temperature of the radiator. The proper way, however, is to connect the heat interchanger 4 to the house heating system at such points that only hot water will flow through the radiator. If the house heating system be a hot water system the radiator or heat interchanger 4 may be connected in the house heating system in the same way as thought it were a house heating radiator. If the house heating system be one employing steam heat, the heat interchanger 4 in m heater must be connected to the boiler below the water level so that only water, and not steam, will circulate through the heat interchanger. For this purpose I have shown two pipes, 23 and 24, connected to the pipes 6 and 7, respectively; each of the pipes 23 and 24 containing a valve 25 which may be closed whenever the gas heater is in use and be opened when hot' water is circulated through the heat radiator through the pipes 23 and 24 connected to the house heating system as heretofore explained.

It will thus be seen that I have produced a sim 1e and novel apparatus or system for efi'ectlvely heating hard water without the objectionable consequences resulting from over heating of such water. It will also be seen that incidentally I am able to supply heated water which will never be so hot as to scald the hands when the water flows thereon from a faucet, as sometimes happens with the ordinary water heating systems which at times deliver a mixture of hot water and steam.

While I have illustrated and described with particularity only a single preferred form of my invention, I do not desire to be limited to the exact structural details thus illustrated and described; but intend to cover all forms and arrangements which come within the definitions of my invention constituting the appended claims.

I claim:

1. In a water heating apparatus, a tank having a water inlet and a water outlet, 2. heat interchanger in the tank, a second heat interchanger outside of the tank and at a lower level than the first heat interchanger, piping connecting the lower ends of the heat interchangers, piping connecting the tops of the heat interchangers, a burner for heating the second heat interchanger, an expansion chamber in the piping above and near the top of the first heat interchanger, a

perature in the expansion chamber and the.

temperature of the water in the tank to supply fuel to the burner.

2. In a Water heating apparatus, a tank having a Water inlet and a Water outlet, a heat interchanger in the tank, a second heat interchanger outside of the tank and at a lower level than the first heat interchanger, means including an expansion chamber connecting the heat interchangers to form a closed circulating system, a burner for heating the second heat interchanger, and means controlled by the temperature of the water in said circulating system and by the temperature of the water in the tank to supply fuel to the burner.

In testimony whereof, I sign this specification.

WALTER G. MILLER. 

